Fix warnings in test suite

[chrisburr]

These warnings have appeared in the test suite and should be fixed:

.pixi/envs/default/lib/python3.11/site-packages/opentelemetry/util/_importlib_metadata.py:32
  /Users/cburr/Development/DIRAC-dev/diracx/.pixi/envs/default/lib/python3.11/site-packages/opentelemetry/util/_importlib_metadata.py:32: DeprecationWarning: SelectableGroups dict interface is deprecated. Use select.
    return EntryPoints(ep for group_eps in eps.values() for ep in group_eps)

diracx-core/tests/test_config_source.py::test_remote_git_config_source_default
  /Users/cburr/Development/DIRAC-dev/diracx/.pixi/envs/default/lib/python3.11/tempfile.py:934: ResourceWarning: Implicitly cleaning up <TemporaryDirectory '/var/folders/1g/q2y74s696ng0v_cmb9sv7qgr0000gn/T/tmpktmy_uve'>
    _warnings.warn(warn_message, ResourceWarning)

diracx-core/tests/test_config_source.py::test_remote_git_config_source_branch
  /Users/cburr/Development/DIRAC-dev/diracx/.pixi/envs/default/lib/python3.11/tempfile.py:934: ResourceWarning: Implicitly cleaning up <TemporaryDirectory '/var/folders/1g/q2y74s696ng0v_cmb9sv7qgr0000gn/T/tmp1d7koa36'>
    _warnings.warn(warn_message, ResourceWarning)

diracx-core/tests/test_entry_points.py::test_all_entry_points_loadable[diracx.cli:config]
  /Users/cburr/Development/DIRAC-dev/diracx/.pixi/envs/default/lib/python3.11/tempfile.py:934: ResourceWarning: Implicitly cleaning up <TemporaryDirectory '/var/folders/1g/q2y74s696ng0v_cmb9sv7qgr0000gn/T/tmpu1kguyaa'>
    _warnings.warn(warn_message, ResourceWarning)